Information processing systems, which handle ever increasing amounts of data, require data storage devices that also have the ability to handle the increasing amounts of data. This data is generally stored on magnetic disks and tapes, and optical devices. The increased amount of data requires an increasing number of disks and tapes to store the data for later usage.
In order to reduce the number of media, disks and tapes for instance, a compaction scheme can be used, such that a lower amount of the media items are used to store the data. The increased number of record media has precipitated the increase in the number of tracks and the number of transitions per track, in order to get more and more data stored on each record media. The limitations of the number of transitions that can be recorded onto the media has led to the use of compaction processes to increase the effective amount of data onto each record media.
It is, therefore, an object of the present invention to provide an enhanced data compression procedure for storing an increased amount of data onto a record media.
The compaction schemes of the prior art were not fast enough to compact a Data Stream presently used to transfer the information to the record media, and to maintain a given data rate for the uncompressed data. Extensive compression hardware was used, together with elaborate buffering schemes in order to match the high speed of the data channels in the transfer of the Data Stream to the record media with that of the slower speed required by the data compression units. The encoding of the data into the compressed data form required extensive logic gates and other hardware, in order to accomplish the control operation of the compression scheme. The decoding of the compressed data then required another section of elaborate logic units and other hardware, to accomplish the reverse, i.e., to make the compressed data usable to the information processing system while handling the data at the speed which present day information processing systems process data.